


Sirius Black and the Engorgement Charm

by Notsalony



Category: Harry Potter - J. K. Rowling
Genre: Anal Sex, Charms Mishap, Complete, Finished, Forced Nudity, Hijinx, M/M, Multi, One Off, One Shot, Other, Public Nudity, School Age Marauders, Sex Bible, Sex Charms, Sex Magic, Tricks, envy - Freeform, sexual healing
Language: English
Status: Completed
Published: 2017-06-18
Updated: 2017-06-18
Packaged: 2018-11-15 15:26:00
Rating: Not Rated
Warnings: Rape/Non-Con, Underage
Chapters: 1
Words: 2,017
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11233824
Author URL: https://archiveofourown.org/users/Notsalony/pseuds/Notsalony
Summary: Sirius is worried he’s not developing fast enough down there so he does a dangerous charm and learns the hard way that sometimes you just have to wait.





	Sirius Black and the Engorgement Charm

**Author's Note:**

> My brain is all over the place. I blame this on my random image display thing in my ideas folder.

Sirius Black was not envious of the new swim professor’s package.  Professor Bane Nott was a recent addition to the school, and often wore only his low cut speedo that was barely more then a skin tight pouch for his genitals and thin straps holding it up.  He’d attended meals in this on more then one occasion and he always wore it for his classes.  The tight Gryffindor red with golden stripes at the side looked practically painted on and left nothing of the man’s ample endowment to the imagination.  And… yeah, if Sirius was seriously honest with himself it did bug him that the teacher was better hung then him.  But what really bothered him, not that he was ever going to admit it was the way Moony always seemed to have his eyes gravitate to that barely packaged sausage.   
  
So maybe he’d been peeved and thrown a tantrum at the edge of the forest, and possibly hexed a stump till it erupted in multiple colors of fireworks.  Which no one could prove now that the stump wasn’t even there anymore, but it drew another student’s attention, a seventh year boy Ravenclaw who mentioned that he figured the teacher used a charm he’d heard about to make himself bigger.  Interested in said charm Sirius listened to the older boy, giving it a grain of salt but followed his instructions and soon found himself in a disused part of the library.   
  
Most of the books here seemed to be on low gravity floating plants but just under the edge of one of the books, he found what he was looking for.  The book in question had a layer of dust on it that impressed Sirius with the sheer amount of disinterest in the book.  But the latch under it was what he’d been looking for.  A quick tug up and it revealed a stash of books and very lude looking magazines full of wizarding photos of people doing all sorts of things.  Sirius felt himself blush and grow hard at the sheer number of things that he was finding in here.  But his eyes finally stopped on the spell book he was looking for in the center of the magazines.   
  
A plain blank book its cover looked like it would be on drab uninteresting spells and if he didn’t know what was really in it, Sirius doubted he’d have ever picked it up.  But as soon as he opened it, his eyes were greeted with all manner of spells that involved sex.  By some of the illustrations alone it seemed you used your cock to cast half of them.  Skimming the pages he finally found the page the boy had indicated he needed.  He was reading through the spell when he caught sight of two wizards flying on a broom naked and fucking on the cover of one of the magazines and felt himself grow harder as he watched.  Oh he was going to need that later, work now, massive masturbation fodder later.  Turning back to the book he looked at the instructions, skimming them again as his eyes kept going back to the magazine.   
  
He pulled himself out of his jeans, pointed his wand at his cock and began to work the wand from base to tip alone the top and from tip to base along the bottom muttering the indicated spell. He never noticed anything telling hime how many times or how long to do the spell so he did it for a good five to ten minutes before he got board and closed the book and picked up the magazine and put the book back.  His cock still hard he decided to go ahead and have a wank right there.   
  
Casting a lubricating charm before he took a hold of himself he frowned.  He felt… thicker.  More firm.  He looked down and it did look like he had possibly added a couple inches, and with a smirk he started wanking.  But after twenty minutes and the need to wank worse then ever and his cock sensitive enough that he shivered at every pass of his hand, Sirius still hadn’t cum and his cock just felt bigger and stiffer by the minute.  Giving up in frustration, he chalked it up to being in such an open place as the library and cleaned up after himself, noting that as he tried to tuck himself away he had to actually undo his jeans and slide his boxers down to get his cock through the flies.   
  
The other shock was that he now hung a few inches well past the leg of his boxers.  Huh, he was bigger.  Nice.  He smiled and then groaned.  The boxers were feeling tight against his hard flesh and also felt too sensitive to touch.  So he quickly stripped off and donned his jeans again tucking his boxers into his back pocket and finishing cleaning up.  He had to stop and adjust himself a dozen times by the time the bell rang indicating the hour and that he was due to go to swim class.  A quick summoning charm had his speedo in his hand and headed for the lake where the class was held.  He was almost there when the denim of his jeans rubbed across his engorged dick head and made him whimper.  He looked down and noticed that not only was there a wet spot where he’d been leaking precum, but it was significantly lower down on his thigh then it should have been.   
  
Frowning he looked around and looked down the top of his trousers to discover a much thicker and larger penis going down his pant leg.  Well fuck.  Maybe it took longer to wear off?  Maybe he just did the spell too long.  It’d all be fine in a while. He’d just go to class show off a little, feel better about himself and then go to the nurse’s station and have a story to tell the boys about how that hot nurse took care of his aching needs.   
  
“You’re late.” Professor Nott crossed his arms over his chest.   
  
“Sorry.  I’ll just duck in here and change.” He blushed his eyes drawn to the man’s large bulge and feeling himself throb with need.  He quickly went into the shed and changed out of his cloths.  But as he tried to get into the pouch of his speedo he blushed at how incredibly tight it was.  While the Professor’s looked painted on, Sirius’ was so stretched it was damn near transparent.  Blushing he heard knocking at the door.   
  
“What’s taking so long Mr. Black?”   
  
“Professor… I.. think I have a problem….” His voice shook.   
  
“What kind of problem.”   
  
“I think I need a different suit sir.”   
  
“And why’s that?”   
  
“I think I might be too big for this one.” Sirius blushed and the Professor came in.   
  
“Black I’ve seen you in your suit, there’s no way that you’re….” He paused and looked at Sirius who blushed, before the uniform tore in half and his cock and balls, which were also slightly swollen, spilled out into plain view.  “I see.” He sighed, pinching the bridge of his nose before bending over and examining the damage.  “I take it you used a charm to make it bigger?”   
  
“Yeah… I…”   
  
“Which one?”   
  
“Which… one?” Sirius blinked.  “There’s more than one?”   
  
“Oh gods.  What did it entail?” So Sirius spelled out the charm for him and the teacher looked at Sirius with first disbelief and then shook his head.  “Well you used a nice one on yourself.  Gideon’s Hammer.  And if you’d read all the instructions you’d have known to do it while you’re soft.”   
  
“What’s that matter?”   
  
“Doing it while hard makes you keep growing until you orgasm.  I’m guessing you haven’t cum yet?”   
  
“I couldn’t…”   
  
“Because of the second side effect.”   
  
“Which is?” Sirius looked afraid to know.   
  
“I’m going to have to so you.” The teacher sighed. “Right turn around.”   
  
“Turn… around… but…”   
  
“No buts but yours.  Turn.” Sirius turned around and blushed as the teacher pulled the ruined speedo down his legs leaving him standing there naked, his cock still trembling as it swelled more.  “Just relax.” The teacher mumbled a lubricating charm and Sirius almost lost it when he felt a firm finger enter his tight ass and seek out his prostate.  He’d touched it before.  Even had a toy he used to hit it just right from time to time.  But fuck me sideways with a two by four did that feel great when the teacher did it.  He started cursing up a storm and was almost there, not caring or noticing that he was leaking like an unkinked fire hose and the good Professor had worked his way up to three fingers.  He barely registered movement behind him.  Just the sense of loss when the fingers were removed.   
  
But then something a hell of a lot bigger then those fingers entered him and Sirius soon found himself sitting on the teacher’s lap.  He moaned and tried to talk but all that came out was wanton begging.  He gave up trying to make sense and just gave himself into the feelings as he howled with pleasure until he eventually came.  Cum rushing out of his swollen swinging balls like he was pissing, hard and fast and too hot to handle, Sirius just kept having the biggest orgasm of his life.  And it seemed to go on forever before the teacher finished in him and Sirius lay there limp and hard, his cock finally stopping it’s torrent of cum.  But almost instantly the desire to cum filled him.   
  
“Professor…” Sirius whimpered as the Professor pulled out and cleaned himself off before redressing.   
  
“I don’t know how sexual you were before, but effectively Gideon’s Hammer is also known as the slut maker.  You’ll be incapable of orgasming without another man fucking you.  That orgasm will stop the swell of your cock, but it’ll remain the size it is now forever until you let as many men as you can climb atop you and ride you to their pleasure to burn the curse out of you.”   
  
“But I….” Sirius looked down at his too large cock.”   
  
“So you can either keep it that size and be horny all the time and never be able to cum again.  Or you can start whoring yourself out as fast as you can.” The teacher shrugged. “Either way, you’ll find wearing trousers difficult for the duration.  Sirius looked at him with confusion.  “My dear boy…” He reached foreword and ran a bit of terry cloth from his towel lightly along Sirius’ length, his whole body spasmed.  “You’re overly tender and sensitive.  Anything covering your monstrous penis now will only make itself unbearable.”   
  
“But how will I…”   
  
“Go to class.  Simple.  6 points from Gryffindor for self induced curses and until you’ve been fucked enough that your penis returns to a reasonable size, I’m instructing the house elves to remove your pants and your trousers from here on out.  And for classes where you would have worn something like your swim suit, you’ll seemly have to go raw.” He reached down and hoisted Sirius up by his elbow.  “Time to face your new life I’m afraid.” Sirius was brought out and exposed to the class who were all shocked by the sheer size of his member now, and as it was explained to them what had happened and what needed to happen there were soon twenty boys with very full pouches of their own and smirks from ear to ear.  Class was held and then they were sent to the showers where Sirius was ridden hard and treated like a fucking post by everyone but his friends.  They waited till they could be alone with him and make him feel cherished and adored.   
  
It took two months before Sirius was cured and capable of having an orgasm from masturbating again.  And it’d be three months after that before he’d dare to try anything out of that book again.  But that, is another story.   
  


~fin~

**Author's Note:**

> Hope you enjoy.


End file.
